Patient warming is a significant concern in many medical situations. In emergency rooms, for example, many of the trauma patients admitted are hypothermic. If their hypothermia is not addressed, these patients can go into shock. Similarly, in hospitals, some adult patients will experience hypothermia during or after surgery. If prolonged, the detrimental physiological consequences of this hypothermia represents a significant risk to these surgical patients.
Hypothermia reduces the blood flow to the appendages of the body in order to protect the vital organs. It is a natural defense mechanism that can only be treated by warming the patient. Studies have shown that such hypothermia may be related to the development of serious postoperative complications, such as impaired platelet function and increased blood loss, resulting in heightened transfusion requirements.
Conventional methods for preventing intraoperative temperature decline in surgical patients include pre-warming a blanket using a blanket warming device and then placing the warmed blanket over the patient. A convection heating device is also available that blows heated air through a duct into a nonwoven blanket placed over the patient. The nonwoven blanket has channels for the heated air to circulate in and is disposable, making cleaning unnecessary. Another product circulates heated water through a blanket in a similar manner. This water filled device, however, is typically placed under the patient.
Known methods such as these for preventing temperature decline are often inefficient and ineffective, particularly in older patients. Convection heating devices, for example, have proven expensive because of the disposable nonwoven blankets, not to mention the energy and maintenance requirements. The high temperatures of the heated air duct in close proximity to anesthetized patients has also raised concerns. In addition, like pre-warmed blankets placed over the patient, they warm the patient inefficiently from above, which has the collateral negative effect of limiting clinical access to the patient from the topside. Both the air and water devices require relatively large amounts of energy, noisy pumps, and significant maintenance in the clinical environment. In light of the shortcomings associated with conventional patient warming devices, a low maintenance patient warming device that efficiently warms a patient to a desired temperature, uses little energy, avoids high temperatures, and overcomes other problems would be desirable.
In the drawings, the same reference numbers identify identical or substantially similar elements or acts. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the Figure number in which that element is first introduced (e.g., element 1104 is first introduced and discussed with respect to FIG. 11).